Embed fonts into the executable, ship release artifacts as bare binaries

Fonts are now baked in with #load and loaded via LoadFontFromMemory
instead of LoadFontEx reading assets/*.ttf from disk, so a build no
longer needs an assets/ folder next to it at runtime - the chdir to
the executable's own directory in main.odin is dead code, removed.

just package / just package-windows now produce a single executable
(build/<name>_<version>_<os>_<arch>[.exe]) instead of a tar.gz/zip,
and the release workflow's upload/release-asset globs and the lld/zip
toolchain package list are updated to match.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

main.odin

@@ -30,8 +30,6 @@ main :: proc() {
     raylib.InitWindow(themes.SCREEN_WIDTH, themes.SCREEN_HEIGHT, "HanjaKanaMun")
     defer raylib.CloseWindow()
     raylib.SetExitKey(.KEY_NULL)
-    // Assets are loaded relative to the executable, so it can be started from anywhere
-    raylib.ChangeDirectory(raylib.GetApplicationDirectory())
     raylib.SetTargetFPS(60)
 
     raylib.InitAudioDevice()